There are millions of single line phone in use throughout the world. These phones are not capable of being connected to more than one phone line at a time. Without the expense of buying a new dual or multiple line phone, many people would like to have the ability of using their existing single line phone to connect to multiple phone lines at the same time. This convenience would allow the conversion of a single line phone to a multi-line phone that would be capable of making conference calls, putting a call on hold with music while making a second call, answering a second line or selecting a phone line on which a call is to be made. Currently there is no device on the market that allows a phone user to add a second or third line to their home or office and to connect all of the lines to an existing single line phone while at the same time having incoming calls on all lines recognized by the single line phone user who controls the selection of incoming calls. Such a convenience would thus allow a single line phone owner to have all the convenience of a multi-line phone without purchasing one. It would also be an advantage if there was an adaptor for connecting multiple separate phone lines to a single line phone that was battery operated thereby eliminating the need for a transformer. Such a device would have to have low power consumption so that the batteries could provide many months of continuous service before replacement was necessary.